Modern wind turbines comprise a plurality of wind turbine rotor blades, typically three blades, each blade having a weight of up to 35 tons and a length of up to 80 meters or longer.
As the size of wind turbines and thus wind turbine blades are still growing, the production facilities and the transport means must be increased to handle blades of the required size. This also increases the demand on logistics and increases the associated costs.
Also, the different parts of a wind turbine blade have different requirements to factors such as the material and structural properties and to the manufacturing processes. This can lead to the blade manufacturing process being complex, labour intensive, and prolonging the production time. As an example the shape and stiffness of the trailing edge significantly influence the overall aeroelastic parameters of the blade as well as the level of noise emitted from the blade. Also, the often rather sharp trailing edge makes this blade part especially sensitive and prone to damage during manufacture and transport. The trailing edge therefore often involves the use of other materials or additional manufacturing steps than for the remaining blade shell.
Wind turbine blades manufactured in parts or in sections for later joining are known. However, there may be problems with obtaining the necessary precision and strength of the joints between the connected blade parts and for safe transfer of loads and moments across the joint. Further, difficulties may arise in connecting the often very large sections without jeopardizing the final shape, stiffness and weight considerations on the blades.